Researchers identified an extraordinary material for implementing thermoelectric devices with the highest efficiency ever recorded.
Thermoelectric generators are quite popular. They can convert the thermal energy into electricity by taking advantage of thermal gradients. In a thermoelectric generator module, one side is hot and the other side is cold and what makes it work is a thermoelectric material that lies in the middle. Heat flows through the material, and some of the heat is converted to electricity.
For high efficiency, the material needs to have extremely low thermal conductivity while still retaining good electrical conductivity. And as the source of heat can be much higher, the material needs to be stable at those temperatures. These challenges make thermoelectric devices difficult to manufacture.
Researchers from Northwestern University and Seoul National University in Korea have recently demonstrated a high performance thermoelectric material. The material used is purified tin selenide in polycrystalline form, which gives the most efficiency ever recorded. The researchers were able to achieve the high conversion rate after identifying and removing an oxidation problem that had degraded performance in earlier studies.
The material can be used in solid-state thermoelectric devices, and the key applications for these devices are in power plants, the automobile industry and glass- and brick-making factories for conversion of heat into electricity.
“Thermoelectric devices are in use, but only in niche applications, such as in the Mars rover,” said Northwestern’s Mercouri Kanatzidis, a chemist who specializes in the design of new materials. “These devices have not caught on like solar cells, and there are significant challenges to making good ones. We are focusing on developing a material that would be low cost and high performance and propel thermoelectric devices into more widespread application.”
The study has been published in the journal Nature Materials.
“This opens the door for new devices to be built from polycrystalline tin selenide pellets and their applications explored,” Kanatzidis said.